Reading and writing data

A short description of the post.

  1. Load the R packages we will use
  1. Download \(C0_2\) emissions per capita from Our World in Data into the directory for this post.

  2. Assign the location of the file to ‘file_csv’. The data should be in the same directory as this file

Read the data into R and assign it to ‘emissions’

file_csv <- here("_posts","2021-03-01-reading-and-writing-data","co-emissions-per-capita.csv")
emissions <- read_csv(file_csv)
  1. Show the first 10 rows (observations of) ‘emissions’
    emissions
    
# A tibble: 22,383 x 4
   Entity      Code   Year `Per capita CO2 emissions`
   <chr>       <chr> <dbl>                      <dbl>
 1 Afghanistan AFG    1949                    0.00191
 2 Afghanistan AFG    1950                    0.0109 
 3 Afghanistan AFG    1951                    0.0117 
 4 Afghanistan AFG    1952                    0.0115 
 5 Afghanistan AFG    1953                    0.0132 
 6 Afghanistan AFG    1954                    0.0130 
 7 Afghanistan AFG    1955                    0.0186 
 8 Afghanistan AFG    1956                    0.0218 
 9 Afghanistan AFG    1957                    0.0343 
10 Afghanistan AFG    1958                    0.0380 
# ... with 22,373 more rows
  1. Start with ‘emissions’ data Then
tidy_emissions
# A tibble: 22,383 x 4
   entity      code   year per_capita_co2_emissions
   <chr>       <chr> <dbl>                    <dbl>
 1 Afghanistan AFG    1949                  0.00191
 2 Afghanistan AFG    1950                  0.0109 
 3 Afghanistan AFG    1951                  0.0117 
 4 Afghanistan AFG    1952                  0.0115 
 5 Afghanistan AFG    1953                  0.0132 
 6 Afghanistan AFG    1954                  0.0130 
 7 Afghanistan AFG    1955                  0.0186 
 8 Afghanistan AFG    1956                  0.0218 
 9 Afghanistan AFG    1957                  0.0343 
10 Afghanistan AFG    1958                  0.0380 
# ... with 22,373 more rows
  1. Start with the ‘tidy_emissions’ THEN
Table 1: Data summary
Name Piped data
Number of rows 221
Number of columns 4
_______________________
Column type frequency:
character 2
numeric 2
________________________
Group variables None

Variable type: character

skim_variable n_missing complete_rate min max empty n_unique whitespace
entity 0 1.00 4 32 0 221 0
code 13 0.94 3 8 0 208 0

Variable type: numeric

skim_variable n_missing complete_rate mean sd p0 p25 p50 p75 p100 hist
year 0 1 2018.00 0.00 2018.00 2018.00 2018.00 2018.00 2018.00 ▁▁▇▁▁
per_capita_co2_emissions 0 1 5.05 5.79 0.03 1.09 3.51 6.65 39.27 ▇▂▁▁▁
  1. 13 observations have a missing code. How are these observations different?
# A tibble: 13 x 4
   entity                     code   year per_capita_co2_emissions
   <chr>                      <chr> <dbl>                    <dbl>
 1 Africa                     <NA>   2018                     1.13
 2 Asia                       <NA>   2018                     4.37
 3 Asia (excl. China & India) <NA>   2018                     4.14
 4 EU-27                      <NA>   2018                     6.87
 5 EU-28                      <NA>   2018                     6.71
 6 Europe                     <NA>   2018                     7.50
 7 Europe (excl. EU-27)       <NA>   2018                     8.39
 8 Europe (excl. EU-28)       <NA>   2018                     9.16
 9 International transport    <NA>   2018                     4.62
10 North America              <NA>   2018                    11.4 
11 North America (excl. USA)  <NA>   2018                     4.75
12 Oceania                    <NA>   2018                    11.4 
13 South America              <NA>   2018                     2.59
Entities that are not countries do not have country codes. 8. Start with tidy_emissions THEN - Use ‘filter’ to extract rows with year == 2018 and without missing codes THEN - use ‘select’ to drop the ‘year’ variable THEN - use ‘rename’ to change the variable ‘entity’ to ‘country’ - assign the output to ‘emissions_2018’
emissions_2018 <- tidy_emissions %>% 
  filter(year == 2018, !is.na(code)) %>% 
  select(-year) %>% 
  rename(country = entity)
  1. Which 15 countries have the highest ‘per_capita_co2_emissions’?
  1. Which 15 countries have the lowest ‘per_capita_co2_emissions’?
  1. Use ‘bind_rows’ to bind together the ‘max_15_emitters’ and ‘min_15_emitters’
  1. Export max_min_15 to 3 file formats
max_min_15 %>% write_csv("max_min_15.csv")
max_min_15 %>% write_tsv("max_min_15.tsv")
max_min_15 %>% write_delim("max_min_15.psv", delim = "|")
  1. Read the 3 file formats into R
max_min_15_csv <- read_csv("max_min_15.csv")
max_min_15_tsv <- read_tsv("max_min_15.tsv")
max_min_15_psv <- read_delim("max_min_15.psv", delim = "|")
  1. Use ‘setdiff’ to check for any differences among ‘max_min_15_csv’
    setdiff(max_min_15_csv,max_min_15_tsv,max_min_15_psv)
    
# A tibble: 0 x 3
# ... with 3 variables: country <chr>, code <chr>,
#   per_capita_co2_emissions <dbl>

Are there any differences?

  1. Reorder ‘country’ in ‘max_min_15’ for plotting and assign to max_min_15_plot_data
  1. Plot ‘max_min_15_plot_data’
    ggplot(data = max_min_15_plot_data,
       mapping = aes(x=per_capita_co2_emissions,y= country)) +
    geom_col() + 
    labs(title = "The top 15 and bottom 15 per capita CO2 emissions",
     subtitle = "for 2018",
     x= NULL,
     y= NULL)
    
  1. Save the plot directory with this post
    ggsave(filename = "preview.png",
       path = here("_posts", "2021-03-01-reading-and-writing-data"))
    
  1. Add preview.png to yaml chuck at the top of this file
preview: preview.png